Episode 20 recap: Luo Xiang Qian was disciplined for the failure of the homemade explosive, and it was Luo Xiang Qian who spoke up first.

Sha Kai's words made everyone unhappy. Sha Kai insisted that he was right, as the explosive was difficult to store and would lose its effectiveness over time. Ye Lan questioned Sha Kai's statement, expressing dissatisfaction with how Sha Kai opposed everything Captain Luo said. Luo Xiang Qian acknowledged that Sha Kai's argument had some merit. The issue of storing the explosive indeed needed attention. However, Luo Xiang Qian wanted to address the matter of rewarding Mu Pa, as he proposed hiring Mu Pa as the team's technician. Not only would Mu Pa be provided with meals, but he would also receive a rice allowance to support his family. Everyone agreed that this was a suitable arrangement, and even Sha Kai eventually expressed his agreement.

The group escorted Mu Pa back home. Mu Pa's wife was surprised to see him standing up, which shocked her. She accepted everyone's advice and expressed her willingness to sever ties with other men and live a good life with Mu Pa. Zhang Biao gave the chestnuts he found to Yao Wa, which deeply moved Wang Lan Zhi. Zhang Biao hummed a tune as he returned to the headquarters, where Luo Xiang Qian was sewing the cap with an unravelled thread. Seeing Zhang Biao so happy, Luo Xiang Qian knew that he had gone to see Wang Lan Zhi. Luo Xiang Qian urged Zhang Biao and Wang Lan Zhi to reconcile and start anew. This time, Zhang Biao did not refuse but said that he needed some time.

In the dormitory, Ku Mei also advised Wang Lan Zhi to reconcile with Zhang Biao. However, Wang Lan Zhi was unwilling to burden him, even if Zhang Biao was willing. She felt that having a child would be a hindrance to him. Luo Xiang Qian conducted an experiment with everyone using explosives. One of the charges failed to detonate, and Mu Pa hurried over. Luo Xiang Qian rushed to protect Mu Pa, but he ended up getting scratched by a flying stone. After being examined by Doctor Yu, it was determined that Luo Xiang Qian had only suffered a minor head injury and had a buzzing sound in his ears. Upon hearing this, Sha Kai came over and made fun of Luo Xiang Qian, saying that he had been lucky this time, but what if he wasn't so fortunate next time and got blown up? Ye Lan criticized Sha Kai for his harsh words, but Luo Xiang Qian pretended not to hear and continued to encourage Mu Pa to carry on with the experiments.

Sha Kai reported Luo Xiang Qian's failure with the homemade explosives to Captain Ma. When Captain Ma heard about it, he was furious. Ye Lan knew that it was Sha Kai who reported the incident and chastised him for only standing by and making fun of the situation, warning him to always leave himself an escape route. Upon learning that Sha Kai had reported the incident with the homemade explosives and that Luo Xiang Qian had been disciplined as a result, Mu Pa became angry at Sha Kai's actions and sought revenge. He grabbed a pickaxe and tried to attack Sha Kai, but luckily, someone intervened and pulled him away. Zhang Biao and Luo Xiang Qian tried to console Mu Pa, explaining that such actions would only complicate matters further, and Luo Xiang Qian would bear even greater responsibility in the future.

Luo Xiang Qian also advised Mu Pa not to hold a grudge against Sha Kai. Safety was the most important thing on the construction site. They should focus on how Mu Pa should continue his work in the future, but regardless of what they do, safety must always come first.

Sha Kai lay on the bed and saw Zhang Biao come back, so he started humming. Zhang Biao said that Mu Pa didn't hit him with the wooden rake, so why was he humming. Sha Kai said that he twisted his waist while dodging the wooden rake, and he also said that it was karma for Luo Xiang Qian because Ye Lan looked like she lost her soul whenever she saw him. Zhang Biao got angry and wanted to hit him. Captain Ma personally came to the First Brigade to investigate and handle the explosion incident. He wanted to give Luo Xiang Qian a serious warning and punishment. Everyone pleaded for Luo Xiang Qian, but in order to remind him to always prioritize safety, he must be given a certain punishment.

Luo Xiang Qian said he would remember it for the rest of his life. Everyone was worried about what kind of punishment Luo Xiang Qian would receive, and they were discussing it outside. Mu Pa couldn't bear it and rushed into the meeting room, asking Captain Ma not to punish Luo Xiang Qian. When everyone heard Mu Pa speak up, they were surprised. Mu Pa talked about how he pretended to be mute to avoid being a soldier in the past, which shocked everyone.

Mu Pa said that he felt hopeless and despondent after being injured in the explosion, but it was Captain Luo who brought him back to life and made him willing to speak again. He couldn't let Captain Luo take the blame for him. Captain Ma encouraged him to make full use of his intelligence and contribute to the construction of the Chengdu-Chongqing Railway. The punishment for Luo Xiang Qian was not to make him a scapegoat, but a strict requirement for a Communist Party member.

Mu Pa was greatly inspired, and he pondered over how to solve the problem of the silent firecracker. In the end, he invented a method of putting the fuse into a bamboo tube, solving the problem of silent firecrackers and safety. Ye Lan named this invention the "Bamboo Tube Firecracker Method," and Luo Xiang Qian asked Ye Lan to write a report to be submitted to the higher-ups for promotion throughout the entire construction site.

During their rest time, the female workers of the First Brigade made hundreds of pairs of gloves for the volunteer soldiers on the Korean front, hoping that they would win the war and return home soon. The workers of the First Brigade were all excited and voluntarily increased their efforts to meet the construction deadline.